1. Field of the Invention
The present invention relates to a shutter drive unit for causing a three-dimensional (3D) stereoscopic image to be expressed by driving shutters of 3D eyeglasses, and a 3D image display system including the same.
2. Description of the Related Art
FIG. 1 is a view showing a concept of 3D eyeglasses.
As shown in FIG. 1, in 3D eyeglasses 1, liquid crystal shutters 2 and 3 are disposed in portions corresponding to right and left lenses of general eyeglasses, respectively.
Also, the liquid crystal (LC) shutters 2 and 3 are turned ON or OFF synchronously with image display by a shutter drive unit, thereby expressing a 3D stereoscopic image.
FIG. 2 is a circuit diagram showing a configuration of a general shutter drive unit.
A shutter drive unit 4 is integrated in the form of a driver IC (Integrated Circuit).
The shutter drive unit 4 includes a driver 5, a driver 6, a drive terminal T1 for the driver 5, and a drive terminal T2 for the driver 6. In this case, the driver 5 drives a capacitive load 2a of the liquid crystal shutter 2. Also, the driver 6 drives a capacitive load 3a of the liquid crystal shutter 3.
The driver 5 is composed of a p-channel MOS (PMOS) transistor PT1 and an n-channel MOS (NMOS) transistor NT1.
A source terminal of the PMOS transistor PT1 is connected to a power source Vdd and a drain terminal thereof is connected to the drive terminal T1.
A source terminal of the NMOS transistor NT1 is connected to a reference potential Vss and a drain terminal thereof is connected to the drive terminal T1.
The PMOS transistor PT1 is turned ON or OFF in accordance with an inverted signal /SWR1 (a mark “/” represents inversion) of a signal SWR1 supplied to a gate terminal of the PMOS transistor PT1.
The NMOS transistor NT1 is turned ON or OFF in accordance with a signal SWR2 supplied to a gate terminal of the NMOS transistor NT1.
The driver 6 is composed of a PMOS transistor PT2 and an n-channel MOS (NMOS) transistor NT2.
A source terminal of the PMOS transistor PT2 is connected to the power source Vdd, and a drain terminal thereof is connected to the drive terminal T2.
A source terminal of the NMOS transistor NT2 is connected to the reference potential Vss, and a drain terminal thereof is connected to the drive terminal T2.
The PMOS transistor PT2 is turned ON or OFF in accordance with an inverted signal /SWL1 of a signal SWL1 supplied to a gate thereof.
The NMOS transistor NT2 is turned ON or OFF in accordance with a signal SWL2 supplied to a gate terminal thereof.
With the shutter drive unit 4, the drivers 5 and 6 supply a voltage at the power source Vdd level, and a voltage at the reference potential Vss level to capacitive loads 2a and 3a as objects of drive of the liquid crystal shutters 2 and 3, thereby turning ON or OFF the liquid crystal shutters 2 and 3, respectively.